In the use of electronic watches, particularly multifunctional digital watches, it is necessary to have switches which enable the user of the watch to select desired display functions, or to set the information being displayed or to illuminate the display by some external light source. In the past, electronic watches have often employed one or more pushbutton switches to control the watch functions. These pushbuttons most often employ a dynamic seal which is necessary to minimize or prevent moisture or other contaminants from entering into the interior of the watch where delicate electronic components can be adversely affected.
Typically, the pushbutton assembly includes a tube having an axially tapered bore for receiving a plunger. An O-ring is disposed around the plunger and a spring is used to provide tension on the pushbutton. Typical prior art pushbuttons are shown in U.S. Pat. No. 3,575,212 to Zellweger et al. issued Sept. 11, 1973, U.S. Pat. No. 3,783,607 to Feurer issued Jan. 8, 1974 and U.S. Pat. No. 4,023,002 to Wuthrich issued May 10, 1977 among others. Switches of the typical pushbutton type are not advantageous in that they are relatively high in cost, provide inadequate sealing and detract from the overall appearance of the watch.
A pushbutton switch which overcame these deficiencies is described in U.S. Pat. No. 4,031,348 issued to Eberhardt on June 21, 1977. This switch comprises a single pushbutton member which includes a button and a shaft, the shaft being disposed within a bore and a counterbore in a watchcase. A resilient, annular washer is disposed about the shaft of the pushbutton member within the counterbore and is shaped to provide sealing engagement with the counterbore and pushbutton. The washer also functions as both a seal and return spring for returning the pushbutton to its initial position after actuation.
Other types of switches for electronic watches have been developed in the prior art. For example, a thin touch-type switch is disclosed in U.S. Pat. No. 4,241,246 issued to Lugaresi on Dec. 23, 1980. Switch constructions for electronic calculator watches are disclosed in U.S. Pat. No. 4,072,004 to Tanaka et al. issued issued Feb. 7, 1978 and in U.S. Pat. No. 4,184,321 issued to Tarusawa on Jan. 22, 1980.
Switch constructions apparently for other uses are disclosed in the following patents: U.S. Pat. No. 3,999,287 issued to Lockhard discloses a rocker switch in which a pair of spaced contacts are embedded in a rocker and resiliently grip a diode therebetween that controls current direction in the circuit; U.S. Pat. No. 4,121,074 issued to Orcutt et al. involves a pressure responsive switch incorporating a rocker member for operating on a contact arm; U.S. Pat. No. 4,172,973 issued to Sano discloses a seesaw switch light-emitting diode mounted on a rocker.
Copending U.S. patent application Ser. No. 273,786 entitled "Rocker Switch" filed on Jun. 15, 1981 in the names of Eberhardt and Carl and of common assignee herewith discloses a rocker switch useful for controlling the functions of an electronic watch. As adopted for use with a watch, the rocker switch is preferably disposed in a recess in a watch case and includes a manually operable actuator bar having a pair of spaced legs projecting through access holes into the watch case to engage switch contact means therein when the actuator bar is rocked. Each leg of the actuator bar includes an offset lip engaging the watch case from the inside to retain the actuator bar in the recess. Resilient washers are positioned around the actuator bar legs between the bar and the bottom of the watchcase recess to provide switch sealing and return-spring functions for the actuator bar.
Other attachments of the watch crystal or lens to the watchcase have been developed in the prior art. For example, the Ratajski U.S. Pat. No. 4,198,811 shows a flat watch crystal mounted between upstanding walls extending along opposite sides of the watchcase. U.S. Pat. No. De. 252,860 issued to Perrin appears to provide a similar case/crystal attachment arrangement.